US3590295A - Homopolar electrical machines - Google Patents

Homopolar electrical machines Download PDF

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Publication number
US3590295A
US3590295A US873398A US3590295DA US3590295A US 3590295 A US3590295 A US 3590295A US 873398 A US873398 A US 873398A US 3590295D A US3590295D A US 3590295DA US 3590295 A US3590295 A US 3590295A
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United States
Prior art keywords
rotor
conductors
machine
disc
compensating
Prior art date
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Expired - Lifetime
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US873398A
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English (en)
Inventor
Anthony Derek Appleton
Robert B Macnab
Joseph Merelie Elliott
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JOHN THOMPSON (PIPEWORK AND ORDNANCE DIVISION) Ltd
Rolls Royce Power Engineering PLC
Original Assignee
International Research and Development Co Ltd
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Assigned to JOHN THOMPSON (PIPEWORK AND ORDNANCE DIVISION) LIMITED reassignment JOHN THOMPSON (PIPEWORK AND ORDNANCE DIVISION) LIMITED CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). 14, EFFECTIVE 1-15-74; 4-8-80 AND 12-8-80 Assignors: INTERNATIONAL RESEARCH & DEVELOPMENT COMPANY LIMITED
Assigned to NORTHERN ENGINEERING INDUSTRIES LIMITED reassignment NORTHERN ENGINEERING INDUSTRIES LIMITED ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: JOHN THOMPSON (PIPEWORK AND ORDANCE DIVISION LIMITED)
Assigned to NORTHERN ENGINEERING INDUSTRIES PLC. reassignment NORTHERN ENGINEERING INDUSTRIES PLC. CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE FEB. 18, 1982 Assignors: NORTHERN ENGINEERING INDUSTRIES LIMITED
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K31/00—Acyclic motors or generators, i.e. DC machines having drum or disc armatures with continuous current collectors
    • H02K31/02—Acyclic motors or generators, i.e. DC machines having drum or disc armatures with continuous current collectors with solid-contact collectors

Definitions

  • the two circuits including series-connected rotor conductors from sections of the rotor lying on opposite sides of a diameter of the rotor and the circuits being maintained continuously as the rotor conductors engage and disengage successive brushes, wherein for the purpose of reducing forces on the stator windings stationary compensating conductors are connected between the machine terminals and the brushes.
  • stationary compensating conductors can be two in number and follow arcuate paths of equal radius coaxial with and in a plane parallel to the rotor.
  • the present invention relates to a homopolar electrical machine having a stator winding, a rotor with a plurality of rotor conductors arranged in a ring around the rotor axis and having first and second contact segments at opposite ends of the rotor conductors which are engaged by first and second sets of brushes interconnected by stationary conductors to produce a continuous current path between the terminals of the machine which includes series-connected rotor conductors.
  • connection of the rotor conductors in series serves to multiply the voltage.
  • the spacing of the brushes is twice that of the associated contact segments so that the series connection is effected alternately between a set of first rotor conductors and a set of second conductors which lie between the first conductors, whilst in intermediate positions each brush bridges a first conductor and a second conductor.
  • stator field windings are formed of coils of superconducting wire that reaction forces on the coils due to the above cause be minimized since the forces are high and such coils can be fragile.
  • a homopolar electrical machine having a stator winding, a rotor with a plurality of rotor conductors arranged in a ring around the rotor axis and having first and second contact segments at opposite ends of the rotor conductors which are engaged by first and second sets of brushes interconnected by stationary conductors to produce two parallel continuous current paths between the terminals of the machine, each path including series-connected rotor conductors from one of two sections of the rotor lying on opposite sides of a diameter of the rotor, characterized in that the series-connected rotor conductors of each section are connected to a terminal of the machine through a stationary compensating conductor so positioned that the current flowing in it produces forces on the stator winding which counteract forces exerted on the winding by current flowing in the stationary conductors.
  • each stationary brush-interconnecting conductor may be considered to be composed of two mutually perpendicular components, a first radial component and a second, smaller, circumferential component.
  • the arcuate paths of the two sections are generally coaxial with the rotor axis and equal in radius and it is possible to calculate the required radius for two compensating conductors disposed along matching arcuate paths.
  • ln disc rotor machines having two sets of rotor conductors forming two disc assemblies mounted back to back the residual sideways forces due to the two assemblies can be made to substantially cancel each other by arranging the connections to the two assemblies so that thesideways forces oppose each other.
  • the compensating conductors of the two assemblies are connected to the machine terminals at diametrically opposite positions. It is also desirable that the connections from the brushes to the terminals which are not made by the compensating conductors should be at the same position for each assembly as the connections of the compensating conductors to the terminals.
  • FIG. 1 shows an arrangement of conducting paths on a disc rotor of a homopolar machine in accordance with our aforesaid copending Pat. application No. 796,081;
  • FIG. 2 is a diagram showing the disposition of certain components of currents flowing in current paths shown in FIG. 1;
  • FIG. 3 is a diagram showing resultant current paths equivalent to the components of currents shown in FIG. 2;
  • FIG. 4 is a diagram showing the disposition of conductors between machine terminals and the rotor circuit of a homopolar machine in accordance with the present invention
  • FIG. 5 shows the application of the invention to a drum-type rotor with axially directed conductors.
  • FIG. 1 a rotor circuit arrangement for a disc-type homopolar machine is shown.
  • a rotor circuit arrangement for a disc-type homopolar machine is shown.
  • Mounted on or constituting the disc are a plurality of radially disposed rotor conductors C1 C24, the inner ends of which are connected to an inner ring of contact segments S, whilst the outer ends are connected to an outer ring of contact segments 8,.
  • the individual segments of each ring are insulated from one another by electrical insulation (not shown) so that the segments are intervening insulation of each ring form a complete segmental ring.
  • Brushes B form an inner set engaging segments S, whilst brushes B form an outer set engaging segments 8,.
  • the brushes of the two sets are interconnected by stationary conductors R,R, shown as dashed lines, as also are the connections I.,-L, conveying current between the rotor circuit and an external circuit by way of the machine terminals T,, T
  • Conductors R,- and connections 15,- are arranged so that the rotor conductors C, are divided into two sections lying on opposite sides of a diameter of the rotor with an equal number of rotor conductors in each section.
  • Each section comprises a series arrangement of rotor conductors and is connected in parallel with a similar series arrangement of the rotor conductors in the other section between the terminals T, and T
  • One of the series arrangements thus follows the conduction path formed by the sequence of elements T,, I..,, C,, R,, C R C R C R C-,, R.,, C,,, R C,,, L;,, T whilst the parallel conduction path is formed by the sequence of elements T,, L
  • the rotor is preferably surrounded by a toroidal stator winding which is both coplanar and coaxial with the rotor disc.
  • the stator winding provides a magnetic field which is generally perpendicular to the rotor disc and which cuts the rotor conducting paths C,-C when the rotor rotates.
  • the stationary conductors R,-R,, are disposed in a plane adjacent to and parallel to the plane of the rotor conductors in such a way that the reaction torque on the rotor is met by the stationary conductors R,-R, and not by the stator field winding.
  • the stationary conductors R,-R do not lie radially with respect to the rotor axis, each being at an acute angle to a radial line, the currentsin these conductors can be resolved into circumferential and radial components.
  • the effect of the radial components of the current in causing circumferential forces on the stator field winding is cancelled by the effect of the rotor conductor currents, which are also radial, but the circumferential components of current give rise to radial forces on the stator winding.
  • FIG. 2 The circumferential components of current in conductors R,R, are indicated in FIG. 2 where they are given the references i,, i, ..i, They may be considered to act along two arcuate current flow paths of radius r, there being one path for each rotor section. These arcuate current flow paths are shown in FIG. 3.
  • each arcuate path must be such that the In practice, the counterflowing currents do not fully cancel the forces experienced on the stator field winding, partly due to manufacturing tolerances and the like permitted in producing, for example, the rotor support disc.
  • the residual force can be further reduced in a double rotor winding of the type shown in FIG. 4, however, by inverting the position of the supply and return conductors to the brushes and compensating conductors X of the second rotor winding relative to the first rotor winding.
  • the currents thus flow downwardly in conductors Y shown at the right-hand side of FIG. 4, and the residual sideways force on the stator winding due to the righthand rotor circuit acts to oppose the residual force due to the left-hand rotor circuit.
  • the effect of the current flowing in the two arcuate paths described is minimized by supplying the current to the rotor circuit by way of compensating conductors of which there can be two forming a ring of radius r disposed adjacent to the stationary conducting paths and in which current flows in the opposite direction to the flow of current in the arcuate paths.
  • this shows the compensating conductors between the machine terminals and brush-sets for' a machine having two sets of rotor conductors, each set being disposed in a disc-shaped assembly and the two assemblies being mounted back-to-back on a support disc.
  • the rotor disc and windings have been omitted for the sake of clarity.
  • FIG. 4 corresponds to the connections suitable for the rotor winding described with reference to FIGS. 1-3, the segments S, and S, of the segmental contact rings being in the positions indicated.
  • the arrangement is particularly suitable for homopolar machines having superconducting windings where the forces acting on the superconducting stator coil due to currents in the stationary brush-interconnecting conductors can be high.
  • FIG. 5 shows a typical drum rotor with axial rotor conductors C, brush sets B, and B stationary conductors R and compensating conductors X.
  • stator field winding would be of toroidal form around the periphery of the disc and the lines of force of the magnetic field would cut the plane of the disc Le. they would be essentially perpendicular to the plane of the paper.
  • two field coils can be used one at each end of and surrounding the rotor.
  • a homopolar electrical machine comprising a stator winding forgenerating a magnetic field, a rotor having mutually insulated rotor conductors which are cut by the magnetic field as the rotor rotates, first and second rings of mutually insulated contact segments located at opposite ends of the rotor conductors each rotor conductor being connected to a segment of one ring and a corresponding segment of the other ring, two sets of brushes, one set cooperating with each ring of contact segments, rotor current terminals, stationary conductors connecting the brushes whereby two parallel current paths are set up through series-connected rotor conductors lying in sections of the rotor disposed on opposite sides of a diameter of the rotor the series connection being effected alternately as the rotor rotates between a first set of rotor conductors and a second set of rotor conductors lying between conductors of the first set in the direction of rotation, the improvement which comprises at least one compensating conductor positioned in relation to the magnetic field cutting the
  • the rotor is of the disc-type with radially disposed rotor conductors and stationary conductors extending in a generally radial direction but at an angle to the rotor conductors characterized in that tors mounted back-to-back characterized in that the compensating conductors associated with one disc are connected to a machine terminal at a position diametrically opposite to the connections of the compensating conductors of the other disc to a machine tenninal.
  • a machine as claimed in claim 1 in which the rotor is of the drum-type with axially disposed rotor conductors and stationary conductors extending in a generally axial direction but following paths at an angle to the rotor conductors in which the machine or each compensating conductor follows a helical path over the rotor surface but in spaced relation thereto.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Windings For Motors And Generators (AREA)
  • Dc Machiner (AREA)
US873398A 1968-11-08 1969-11-03 Homopolar electrical machines Expired - Lifetime US3590295A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5313668 1968-11-08

Publications (1)

Publication Number Publication Date
US3590295A true US3590295A (en) 1971-06-29

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ID=10466770

Family Applications (1)

Application Number Title Priority Date Filing Date
US873398A Expired - Lifetime US3590295A (en) 1968-11-08 1969-11-03 Homopolar electrical machines

Country Status (5)

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US (1) US3590295A (enrdf_load_stackoverflow)
CH (1) CH499916A (enrdf_load_stackoverflow)
DE (1) DE1955666A1 (enrdf_load_stackoverflow)
FR (1) FR2022921A1 (enrdf_load_stackoverflow)
GB (1) GB1229300A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4503349A (en) * 1983-07-29 1985-03-05 Westinghouse Electric Corp. Self-excited high current DC electrical pulse generator
US4710665A (en) * 1986-09-29 1987-12-01 Westinghouse Electric Corp. Homopolar dynamoelectric machine with self-compensating current collector
US5032748A (en) * 1988-11-11 1991-07-16 Sumitomo Heavy Industries, Ltd. Superconducting DC machine
US5278470A (en) * 1990-07-06 1994-01-11 Neag Zacharias J Homopolar machine which acts as a direct current (DC) high voltage generator or motor
US20040021387A1 (en) * 2002-08-01 2004-02-05 Whitesell Eric James Homopolar generator

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1255838A (en) * 1916-03-20 1918-02-05 Rudolf Knoll Dynamo-electric machinery.
US1327349A (en) * 1917-09-13 1920-01-06 Robert V Morse Homopolar magnetic circuit
CA637339A (en) * 1962-02-27 J. Funk Cornelius Full flux dynamo electric machine
US3229133A (en) * 1963-03-08 1966-01-11 Sears Anthony Direct current homopolar generators
US3497739A (en) * 1967-01-03 1970-02-24 Intern Research & Dev Co Ltd T Homopolar electrical machines

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA637339A (en) * 1962-02-27 J. Funk Cornelius Full flux dynamo electric machine
US1255838A (en) * 1916-03-20 1918-02-05 Rudolf Knoll Dynamo-electric machinery.
US1327349A (en) * 1917-09-13 1920-01-06 Robert V Morse Homopolar magnetic circuit
US3229133A (en) * 1963-03-08 1966-01-11 Sears Anthony Direct current homopolar generators
US3497739A (en) * 1967-01-03 1970-02-24 Intern Research & Dev Co Ltd T Homopolar electrical machines

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4503349A (en) * 1983-07-29 1985-03-05 Westinghouse Electric Corp. Self-excited high current DC electrical pulse generator
AU573595B2 (en) * 1983-07-29 1988-06-16 Westinghouse Electric Corporation Self-excited high current d.c. electrical pulse generator
US4710665A (en) * 1986-09-29 1987-12-01 Westinghouse Electric Corp. Homopolar dynamoelectric machine with self-compensating current collector
US5032748A (en) * 1988-11-11 1991-07-16 Sumitomo Heavy Industries, Ltd. Superconducting DC machine
US5278470A (en) * 1990-07-06 1994-01-11 Neag Zacharias J Homopolar machine which acts as a direct current (DC) high voltage generator or motor
US20040021387A1 (en) * 2002-08-01 2004-02-05 Whitesell Eric James Homopolar generator

Also Published As

Publication number Publication date
GB1229300A (enrdf_load_stackoverflow) 1971-04-21
CH499916A (de) 1970-11-30
DE1955666A1 (de) 1970-06-18
FR2022921A1 (enrdf_load_stackoverflow) 1970-08-07

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AS Assignment

Owner name: NORTHERN ENGINEERING INDUSTRIES LIMITED, NEI HOUSE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:JOHN THOMPSON (PIPEWORK AND ORDANCE DIVISION LIMITED);REEL/FRAME:003864/0376

Effective date: 19801208

AS Assignment

Owner name: NORTHERN ENGINEERING INDUSTRIES PLC.

Free format text: CHANGE OF NAME;ASSIGNOR:NORTHERN ENGINEERING INDUSTRIES LIMITED;REEL/FRAME:004101/0161

Effective date: 19821124